2012
American Epilepsy Society (Abst. 1.115)
Efficacy of video-EEG in the diagnosis and treatment of altered mental status in the elderly population
Authors: O. Laban-Grant, N. R. Thakur, S. Mesad, J. Lee, T. Wojohk, C. C. Lambrakis, M. E. Lancman
Rationale:
Alteration of mental status in elderly patients is a common occurrence and frequently of multi-factorial etiology. EEG is frequently part of the diagnostic evaluation in patients where encephalopathy persists despite adequate treatment of the presumable underlying causation. The aim of this study was to evaluate the yield of VEEG monitoring compared to that of the routine EEG in eliciting an accurate diagnosis which would guide treatment of altered mental status in elderly patients.
Methods:
A review of Northeast Regional Epilepsy Group records from a single community hospital from February 2009 until June 2012 identified 82 consecutive patients (32 males and 50 females), 60 years old or older (range 60-97, mean 78.7 SD 9.4), who had VEEG monitoring performed due to persistent altered mental status despite adequate treatment of the presumed underlying etiology. Patients with clinical seizures or status epilepticus at the time of onset of the VEEG monitoring were excluded from the study. The following information was obtained retrospectively: results of the VEEG, results of the previous recent routine EEG or if not available, first hour of the VEEG study, the history of seizures (19/82 patients - 23.2%), reported seizure at the onset of the altered mental status (16/82 patients - 19.5%), and recommendations regarding initiation or changes in treatment regimens with respect to antiseizure medications.
Results:
The VEEG was abnormal in 69 patients (84%). Epileptogenic abnormalities were present in 34 of abnormal studies (49%). In 19 patients, seizures were also recorded (27%). The VEEG revealed dissimilar findings compared to the routine EEG or initial hour of the VEEG in 24 patients (29%). These new findings were considered epileptogenic in 17 patients (71%). Based on these findings, antiepileptic medications were started in 11 patients (16% of all patients). Fifty three patients in our group had no history of seizures in the past or at the presentation of altered mental status. In this subgroup, the VEEG was abnormal in 42 patients (79%). Epileptogenic abnormalities were identified in 15 patients (36%) and seizures were present in 7 patients (17%). The VEEG revealed new findings compared to the routine/initial EEG in 14 patients in this subgroup (26%). New epileptogenic abnormalities were identified in 10 out of 14 studies (71%). Antiepileptic medications were started in 8 patients based solely on the VEEG study (15% of patients who had no history of seizures in past or at the presentation of altered mental status).
Conclusions:
The VEEG provided valuable clinical information compared to the routine EEG in a significant number of patients whose etiology of altered mental status remained unclear. The yield of VEEG was comparable in the subgroup of patients who had no history of seizures. Our study underscores the importance of maintaining a high clinical suspicion for seizures and the usefulness of the VEEG in evaluating alteration in mental status in elderly patients.